PERSIA (IRAN), a kingdom of western Asia, bOunded on the north by the Caspian sea and the Transcaucasian and Trans caspian territories of Russia; on the east by Turkistan, Afghan istan and Baluchistan; on the south by the Persian gulf, and the Oman gulf of the Arabian sea, and on the west by Turkey in Asia and the new State of Iraq.
Frontiers.—The frontier from Mt. Ararat to Astara on the Caspian sea is that laid down in the treaty of Turmanchai (Feb. 22, 1828) and further defined in a Convention of July 8, 1893. The boundary between Russia and Persia starts from the slopes of Mt. Ararat (Aghri Dagh) and runs north-east to the Aras river, which it follows to lat. 48° E. It then runs for about 35 m. south-east through the Mughan steppes to Pilsowar on the Bulgharu river and then south with a bend to the west, to the Astara river and port, whence it follows the shore of the Caspian until it touches the bay of Hasan Quli, north of Astarabad. East of the Caspian and beginning at Hasan Quli Bay the river Atrek serves as the frontier as far as Chat. It then extends east and south-east to Sarakhs on the Tejen river. The frontier east of the Caspian was defined by the Akhal-Khurasan Boundary Con vention of Dec. 21, 1881, and the Frontier Convention of July 8, 1893, which separates Persia from Afghanistan and British India.
The eastern frontier extends from Sarakhs on the north to a point on the coast of the Gulf of Oman near Gwattar, a dis tance of some Boo m. first following the river Tejen, or Hari Rud, to a point near Kuhsan, thence almost due south to the border of Seistan in Lat. 31 N. It then follows the line fixed by Sir F. Goldsmid in 1872 and by Sir A. H. MacMahon in 1903-05 to Kuh-i-Malik Siah. From this point to the sea the frontier separates Persian territory from British Baluchistan and runs south-east to Kuhak and then south-west to Gwattar. This last section was determined by Sir F. Goldsmid's Commission in 1871.
The south boundary is the coast line from the mouth of the Shatt-el-Arab to the vicinity of Gwattar, a distance of some 87o m. The islands in the Persian Gulf nearest to the Persian shore
are Persian territory; they are, from east to west, Hormuz, Larak, Qishm, Henjam, Farur, Qais, Hinderabi, Shaikh Shu'aib Kharag and Kharagu.
Southwards from Mt. Ararat the frontier dividing Persia first from Turkey later from Iraq, extends for about 700 m. until it cuts the left bank of the river Shatt-el-Arab about 12 m. above Mohammerah, whence it follows the high-water mark line of the river to its mouth at Qasbah opposite Fao, leaving the fairway channel in Turkish, now Iraq, territory. This is the line referred to in the Treaty of Erzeroum of 1847, as finally demarcated in 1914 by Perso-Turkish Commissioners, assisted by British and Russian Commissioners with arbitral powers, appointed in virtue of a special agreement concluded in 1913 between Persian and Turkish plenipotentiaries at Constantinople. (P. Z. C.) Persia lies within the great Alpine-Himalayan fold system, forming the connecting link between the Taurus structures and those of Afghanistan and Baluchistan. It may be divided into three major zones:— I. The Elburz (Elbrus) mountains—folded mountains with a thick sedimentary series showing movement towards the north. Large volcanoes are situated in these ranges.
2. Central Persia—a high plateau region but with large depres sions; old crystalline rocks, early Palaeozoics and Mesozoics poorly developed. Volcanoes active throughout the Tertiary.
3. The Zagros system—the mountain belt of S.W. and S. Persia, strongly folded and overthrust structures, the movement having been directed against the Arabian foreland. Some Palaeo zoic rocks, thick Cretaceous and Tertiary series.
Geological History.—Nothing is known of the pre-Palaeozoic history of Persia. Ancient crystalline rocks, granite, gneiss and schists have been described from many localities, but they may represent in part metamorphosed Palaeozoic sediments.